Abstract
OBJECTIVE: To examine the mediating effect of childhood abuse on sexual orientation disparities in tobacco and alcohol use during adolescence. METHODS: We carried out analyses with data from over 62,000 women in the ongoing Nurses' Health Study II cohort who provided information on sexual orientation, childhood abuse occurring by age 11, and tobacco and alcohol use in adolescence. We used multivariate regression analyses, controlling for confounders, to estimate the mediating effect of childhood abuse on the association between sexual orientation and tobacco and alcohol use in adolescence. RESULTS: Lesbian and bisexual orientation and childhood abuse were positively associated with greater risk of tobacco and alcohol use during adolescence. For lesbians, the estimated proportion of excess tobacco and alcohol use in adolescence relative to use among heterosexual women that was mediated by abuse in childhood ranged from 7 to 18%; for bisexual women, the estimated proportion of excess use mediated by abuse ranged from 6 to 13%. CONCLUSIONS: Elevated childhood abuse in lesbian and bisexual women partially mediated excess tobacco and alcohol use in adolescence relative to heterosexual women. Interventions to prevent child abuse may reduce sexual orientation disparities in some of the leading causes of cancer in women.